<!DOCTYPE html><html lang="zh-CN" data-theme="light"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width,initial-scale=1"><title>LockSupport详解 | Kylin</title><meta name="keywords" content="JUC,LockSupport"><meta name="author" content="Kylin"><meta name="copyright" content="Kylin"><meta name="format-detection" content="telephone=no"><meta name="theme-color" content="#ffffff"><meta name="description" content="概念 LockSupport是用来创建锁和其他同步类的基本线程阻塞原语。 LockSupport中的park()和unpark()的作用分别是阻塞线程和解除阻塞线程。 使用三种让线程等待和唤醒的方法  synchronized+wait+notify lock+await+signal LockSupport+park+unpark  JUC之synchronized和Lock | Kylin (">
<meta property="og:type" content="article">
<meta property="og:title" content="LockSupport详解">
<meta property="og:url" content="https://www.codekylin.cn/20208.html">
<meta property="og:site_name" content="Kylin">
<meta property="og:description" content="概念 LockSupport是用来创建锁和其他同步类的基本线程阻塞原语。 LockSupport中的park()和unpark()的作用分别是阻塞线程和解除阻塞线程。 使用三种让线程等待和唤醒的方法  synchronized+wait+notify lock+await+signal LockSupport+park+unpark  JUC之synchronized和Lock | Kylin (">
<meta property="og:locale" content="zh_CN">
<meta property="og:image" content="https://qiniu.codekylin.cn/github/img/img/wallhaven-1j66e3.jpg">
<meta property="article:published_time" content="2021-12-25T09:21:04.000Z">
<meta property="article:modified_time" content="2022-07-12T11:42:50.029Z">
<meta property="article:author" content="Kylin">
<meta property="article:tag" content="JUC">
<meta property="article:tag" content="LockSupport">
<meta name="twitter:card" content="summary">
<meta name="twitter:image" content="https://qiniu.codekylin.cn/github/img/img/wallhaven-1j66e3.jpg"><link rel="shortcut icon" href="https://qiniu.codekylin.cn/img/20200807181548.png"><link rel="canonical" href="https://www.codekylin.cn/20208"><link rel="preconnect" href="//cdn.jsdelivr.net"/><link rel="preconnect" href="//www.google-analytics.com" crossorigin=""/><link rel="preconnect" href="//hm.baidu.com"/><link rel="preconnect" href="//fonts.googleapis.com" crossorigin=""/><meta name="google-site-verification" content="gzeyWstt6NoTZKh7YFYNLNziL8HIZ8YH2Ug7xTDX5-Y"/><link rel="stylesheet" href="/css/index.css"><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@fortawesome/fontawesome-free/css/all.min.css" media="print" onload="this.media='all'"><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/node-snackbar/dist/snackbar.min.css" media="print" onload="this.media='all'"><script>var _hmt = _hmt || [];
(function() {
  var hm = document.createElement("script");
  hm.src = "https://hm.baidu.com/hm.js?f76c34daefe747deee7c7be3ead2ba80";
  var s = document.getElementsByTagName("script")[0]; 
  s.parentNode.insertBefore(hm, s);
})();
</script><script async="async" src="https://www.googletagmanager.com/gtag/js?id=UA-159334016-1"></script><script>window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'UA-159334016-1');
</script><link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Titillium+Web" media="print" onload="this.media='all'"><script>const GLOBAL_CONFIG = { 
  root: '/',
  algolia: undefined,
  localSearch: {"path":"search.xml","languages":{"hits_empty":"找不到您查询的内容：${query}"}},
  translate: {"defaultEncoding":2,"translateDelay":0,"msgToTraditionalChinese":"繁","msgToSimplifiedChinese":"简"},
  noticeOutdate: {"limitDay":90,"position":"top","messagePrev":"自上次更新以来已经","messageNext":"天，文章的内容可能已过时或存在差异。"},
  highlight: {"plugin":"highlighjs","highlightCopy":true,"highlightLang":true,"highlightHeightLimit":false},
  copy: {
    success: '复制成功',
    error: '复制错误',
    noSupport: '浏览器不支持'
  },
  relativeDate: {
    homepage: false,
    post: false
  },
  runtime: '天',
  date_suffix: {
    just: '刚刚',
    min: '分钟前',
    hour: '小时前',
    day: '天前',
    month: '个月前'
  },
  copyright: {"limitCount":50000,"languages":{"author":"作者: Kylin","link":"链接: ","source":"来源: Kylin","info":"著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。"}},
  lightbox: 'fancybox',
  Snackbar: {"chs_to_cht":"你已切换为繁体","cht_to_chs":"你已切换为简体","day_to_night":"你已切换为深色模式","night_to_day":"你已切换为浅色模式","bgLight":"#FF0000","bgDark":"#2d3035","position":"bottom-left"},
  source: {
    jQuery: 'https://cdn.jsdelivr.net/npm/jquery@latest/dist/jquery.min.js',
    justifiedGallery: {
      js: 'https://cdn.jsdelivr.net/npm/justifiedGallery/dist/js/jquery.justifiedGallery.min.js',
      css: 'https://cdn.jsdelivr.net/npm/justifiedGallery/dist/css/justifiedGallery.min.css'
    },
    fancybox: {
      js: 'https://cdn.jsdelivr.net/npm/@fancyapps/fancybox@latest/dist/jquery.fancybox.min.js',
      css: 'https://cdn.jsdelivr.net/npm/@fancyapps/fancybox@latest/dist/jquery.fancybox.min.css'
    }
  },
  isPhotoFigcaption: false,
  islazyload: true,
  isanchor: false
}</script><script id="config-diff">var GLOBAL_CONFIG_SITE = { 
  isPost: true,
  isHome: false,
  isHighlightShrink: false,
  isToc: true,
  postUpdate: '2022-07-12 19:42:50'
}</script><noscript><style type="text/css">
  #nav {
    opacity: 1
  }
  .justified-gallery img {
    opacity: 1
  }

  #recent-posts time,
  #post-meta time {
    display: inline !important
  }
</style></noscript><script>(win=>{
    win.saveToLocal = {
      set: function setWithExpiry(key, value, ttl) {
        if (ttl === 0) return
        const now = new Date()
        const expiryDay = ttl * 86400000
        const item = {
          value: value,
          expiry: now.getTime() + expiryDay,
        }
        localStorage.setItem(key, JSON.stringify(item))
      },

      get: function getWithExpiry(key) {
        const itemStr = localStorage.getItem(key)

        if (!itemStr) {
          return undefined
        }
        const item = JSON.parse(itemStr)
        const now = new Date()

        if (now.getTime() > item.expiry) {
          localStorage.removeItem(key)
          return undefined
        }
        return item.value
      }
    }
  
    win.getScript = url => new Promise((resolve, reject) => {
      const script = document.createElement('script')
      script.src = url
      script.async = true
      script.onerror = reject
      script.onload = script.onreadystatechange = function() {
        const loadState = this.readyState
        if (loadState && loadState !== 'loaded' && loadState !== 'complete') return
        script.onload = script.onreadystatechange = null
        resolve()
      }
      document.head.appendChild(script)
    })
  
      win.activateDarkMode = function () {
        document.documentElement.setAttribute('data-theme', 'dark')
        if (document.querySelector('meta[name="theme-color"]') !== null) {
          document.querySelector('meta[name="theme-color"]').setAttribute('content', '#0d0d0d')
        }
      }
      win.activateLightMode = function () {
        document.documentElement.setAttribute('data-theme', 'light')
        if (document.querySelector('meta[name="theme-color"]') !== null) {
          document.querySelector('meta[name="theme-color"]').setAttribute('content', '#ffffff')
        }
      }
      const t = saveToLocal.get('theme')
    
          const isDarkMode = window.matchMedia('(prefers-color-scheme: dark)').matches
          const isLightMode = window.matchMedia('(prefers-color-scheme: light)').matches
          const isNotSpecified = window.matchMedia('(prefers-color-scheme: no-preference)').matches
          const hasNoSupport = !isDarkMode && !isLightMode && !isNotSpecified

          if (t === undefined) {
            if (isLightMode) activateLightMode()
            else if (isDarkMode) activateDarkMode()
            else if (isNotSpecified || hasNoSupport) {
              const now = new Date()
              const hour = now.getHours()
              const isNight = hour <= 6 || hour >= 18
              isNight ? activateDarkMode() : activateLightMode()
            }
            window.matchMedia('(prefers-color-scheme: dark)').addListener(function (e) {
              if (saveToLocal.get('theme') === undefined) {
                e.matches ? activateDarkMode() : activateLightMode()
              }
            })
          } else if (t === 'light') activateLightMode()
          else activateDarkMode()
        
      const asideStatus = saveToLocal.get('aside-status')
      if (asideStatus !== undefined) {
        if (asideStatus === 'hide') {
          document.documentElement.classList.add('hide-aside')
        } else {
          document.documentElement.classList.remove('hide-aside')
        }
      }
    
    const fontSizeVal = saveToLocal.get('global-font-size')
    if (fontSizeVal !== undefined) {
      document.documentElement.style.setProperty('--global-font-size', fontSizeVal + 'px')
    }
    })(window)</script><link rel="stylesheet" href="https://qiniu.codekylin.cn/github/img/img/custom.css"><link rel="stylesheet" href="//at.alicdn.com/t/font_1993646_z05rabxf05h.css"><link rel="stylesheet" href="https://qiniu.codekylin.cn/github/img/img/icon.css"><meta name="generator" content="Hexo 5.4.0"><link rel="alternate" href="/atom.xml" title="Kylin" type="application/atom+xml">
</head><body><div id="web_bg"></div><div id="sidebar"><div id="menu-mask"></div><div id="sidebar-menus"><div class="author-avatar"><img class="avatar-img" data-lazy-src="https://qiniu.codekylin.cn/img/20200807181526.jpg" onerror="onerror=null;src='https://qiniu.codekylin.cn/github/img/friend_404.gif'" alt="avatar"/></div><div class="site-data"><div class="data-item is-center"><div class="data-item-link"><a href="/archives/"><div class="headline">文章</div><div class="length-num">362</div></a></div></div><div class="data-item is-center"><div class="data-item-link"><a href="/tags/"><div class="headline">标签</div><div class="length-num">427</div></a></div></div><div class="data-item is-center"><div class="data-item-link"><a href="/categories/"><div class="headline">分类</div><div class="length-num">101</div></a></div></div></div><hr/><div class="menus_items"><div class="menus_item"><a class="site-page" href="/"><i class="fa-fw fa fa-home"></i><span> 首页</span></a></div><div class="menus_item"><a class="site-page" href="/archives/"><i class="fa-fw fa fa-archive"></i><span> 时间轴</span></a></div><div class="menus_item"><a class="site-page" href="/tags/"><i class="fa-fw fa fa-tags"></i><span> 标签</span></a></div><div class="menus_item"><a class="site-page" href="/categories/"><i class="fa-fw fa fa-folder-open"></i><span> 分类</span></a></div><div class="menus_item"><a class="site-page" href="/link/"><i class="fa-fw fa fa-link"></i><span> 友链</span></a></div><div class="menus_item"><a class="site-page" href="/about/"><i class="fa-fw fa fa-heart"></i><span> 关于</span></a></div></div></div></div><div class="post" id="body-wrap"><header class="post-bg" id="page-header" style="background-image: url('https://qiniu.codekylin.cn/github/img/img/wallhaven-1j66e3.jpg')"><nav id="nav"><span id="blog_name"><a id="site-name" href="/">Kylin</a></span><div id="menus"><div id="search-button"><a class="site-page social-icon search"><i class="fas fa-search fa-fw"></i><span> 搜索</span></a></div><div class="menus_items"><div class="menus_item"><a class="site-page" href="/"><i class="fa-fw fa fa-home"></i><span> 首页</span></a></div><div class="menus_item"><a class="site-page" href="/archives/"><i class="fa-fw fa fa-archive"></i><span> 时间轴</span></a></div><div class="menus_item"><a class="site-page" href="/tags/"><i class="fa-fw fa fa-tags"></i><span> 标签</span></a></div><div class="menus_item"><a class="site-page" href="/categories/"><i class="fa-fw fa fa-folder-open"></i><span> 分类</span></a></div><div class="menus_item"><a class="site-page" href="/link/"><i class="fa-fw fa fa-link"></i><span> 友链</span></a></div><div class="menus_item"><a class="site-page" href="/about/"><i class="fa-fw fa fa-heart"></i><span> 关于</span></a></div></div><div id="toggle-menu"><a class="site-page"><i class="fas fa-bars fa-fw"></i></a></div></div></nav><div id="post-info"><h1 class="post-title">LockSupport详解</h1><div id="post-meta"><div class="meta-firstline"><span class="post-meta-date"><i class="far fa-calendar-alt fa-fw post-meta-icon"></i><span class="post-meta-label">发表于</span><time class="post-meta-date-created" datetime="2021-12-25T09:21:04.000Z" title="发表于 2021-12-25 17:21:04">2021-12-25</time><span class="post-meta-separator">|</span><i class="fas fa-history fa-fw post-meta-icon"></i><span class="post-meta-label">更新于</span><time class="post-meta-date-updated" datetime="2022-07-12T11:42:50.029Z" title="更新于 2022-07-12 19:42:50">2022-07-12</time></span><span class="post-meta-categories"><span class="post-meta-separator">|</span><i class="fas fa-inbox fa-fw post-meta-icon"></i><a class="post-meta-categories" href="/categories/Java/">Java</a><i class="fas fa-angle-right post-meta-separator"></i><i class="fas fa-inbox fa-fw post-meta-icon"></i><a class="post-meta-categories" href="/categories/Java/JUC/">JUC</a></span></div><div class="meta-secondline"><span class="post-meta-separator">|</span><span class="post-meta-wordcount"><i class="far fa-file-word fa-fw post-meta-icon"></i><span class="post-meta-label">字数总计:</span><span class="word-count">1.8k</span><span class="post-meta-separator">|</span><i class="far fa-clock fa-fw post-meta-icon"></i><span class="post-meta-label">阅读时长:</span><span>7分钟</span></span></div></div></div></header><main class="layout" id="content-inner"><div id="post"><article class="post-content" id="article-container"><h2 id="概念"><a href="#概念" class="headerlink" title="概念"></a>概念</h2><p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225174538717.png" alt="image-20211225174538717"></p>
<p>LockSupport是用来创建锁和其他同步类的基本线程阻塞原语。</p>
<p>LockSupport中的<code>park()</code>和<code>unpark()</code>的作用分别是阻塞线程和解除阻塞线程。</p>
<h2 id="使用"><a href="#使用" class="headerlink" title="使用"></a>使用</h2><p>三种让线程等待和唤醒的方法</p>
<ol>
<li>synchronized+wait+notify</li>
<li>lock+await+signal</li>
<li>LockSupport+park+unpark</li>
</ol>
<p><a target="_blank" rel="noopener" href="https://codekylin.cn/28239.html">JUC之synchronized和Lock | Kylin (codekylin.cn)</a></p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/20200924161719.png" alt="synchronized和lock"></p>
<ol>
<li>使用Object中的<code>wait()</code>方法让线程等待，使用Object中的<code>notify()</code>方法唤醒线程。</li>
<li>使用JUC包中的Condition的<code>await()</code>方法让线程等待，使用<code>signal()</code>方法唤醒线程。</li>
<li>LockSupport类可以阻塞当前线程已经唤醒指定被阻塞的线程。</li>
</ol>
<h3 id="synchronized"><a href="#synchronized" class="headerlink" title="synchronized"></a>synchronized</h3><p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225180951299.png" alt="image-20211225180951299"></p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">package</span> com.kylin;</span><br><span class="line"></span><br><span class="line"><span class="comment">/**</span></span><br><span class="line"><span class="comment"> * <span class="doctag">@author</span> kylin</span></span><br><span class="line"><span class="comment"> */</span></span><br><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">SynchronizedDemo</span> </span>&#123;</span><br><span class="line"></span><br><span class="line">    <span class="keyword">static</span> Object objectLock = <span class="keyword">new</span> Object();</span><br><span class="line"></span><br><span class="line">    <span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">main</span><span class="params">(String[] args)</span> </span>&#123;</span><br><span class="line">        <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            <span class="keyword">synchronized</span> (objectLock) &#123;</span><br><span class="line">                System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------come in&quot;</span>);</span><br><span class="line">                <span class="keyword">try</span> &#123;</span><br><span class="line">                    objectLock.wait();</span><br><span class="line">                &#125; <span class="keyword">catch</span> (InterruptedException e) &#123;</span><br><span class="line">                    e.printStackTrace();</span><br><span class="line">                &#125;</span><br><span class="line">                System.out.println(Thread.currentThread().getName()+<span class="string">&quot;---------被唤醒&quot;</span>);</span><br><span class="line">            &#125;</span><br><span class="line">        &#125;, <span class="string">&quot;A&quot;</span>).start();</span><br><span class="line"></span><br><span class="line">        <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            <span class="keyword">synchronized</span> (objectLock) &#123;</span><br><span class="line">                objectLock.notify();</span><br><span class="line">                System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------通知&quot;</span>);</span><br><span class="line">            &#125;</span><br><span class="line">        &#125;, <span class="string">&quot;B&quot;</span>).start();</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>A线程让线程暂停，B线程唤醒A线程执行。</p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225181056398.png" alt="image-20211225181056398"></p>
<p>此时一切正常。接着把同步代码快注释</p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225181252637.png" alt="image-20211225181252637"></p>
<p>运行抛出<code>java.lang.IllegalMonitorStateException</code>异常。说明<code>wait</code>和<code>notify</code>是无法单独脱离<code>synchronized</code>使用的。</p>
<p>接着我们让A线程运行先暂停3秒钟，确保B线程先运行。也就是notify和wait先后过程调换，先notify再wait。</p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225181928899.png" alt="image-20211225181928899"></p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">package</span> com.kylin;</span><br><span class="line"></span><br><span class="line"><span class="keyword">import</span> java.util.concurrent.TimeUnit;</span><br><span class="line"></span><br><span class="line"><span class="comment">/**</span></span><br><span class="line"><span class="comment"> * <span class="doctag">@author</span> kylin</span></span><br><span class="line"><span class="comment"> */</span></span><br><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">SynchronizedDemo</span> </span>&#123;</span><br><span class="line"></span><br><span class="line">    <span class="keyword">static</span> Object objectLock = <span class="keyword">new</span> Object();</span><br><span class="line"></span><br><span class="line">    <span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">main</span><span class="params">(String[] args)</span> </span>&#123;</span><br><span class="line">        <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            <span class="comment">//暂停3秒钟</span></span><br><span class="line">            <span class="keyword">try</span> &#123;</span><br><span class="line">                TimeUnit.SECONDS.sleep(<span class="number">3</span>);</span><br><span class="line">            &#125; <span class="keyword">catch</span> (InterruptedException e) &#123;</span><br><span class="line">                e.printStackTrace();</span><br><span class="line">            &#125;</span><br><span class="line">            <span class="keyword">synchronized</span> (objectLock) &#123;</span><br><span class="line">                System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------come in&quot;</span>);</span><br><span class="line">                <span class="keyword">try</span> &#123;</span><br><span class="line">                    objectLock.wait();</span><br><span class="line">                &#125; <span class="keyword">catch</span> (InterruptedException e) &#123;</span><br><span class="line">                    e.printStackTrace();</span><br><span class="line">                &#125;</span><br><span class="line">                System.out.println(Thread.currentThread().getName()+<span class="string">&quot;---------被唤醒&quot;</span>);</span><br><span class="line">            &#125;</span><br><span class="line">        &#125;, <span class="string">&quot;A&quot;</span>).start();</span><br><span class="line"></span><br><span class="line">        <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            <span class="keyword">synchronized</span> (objectLock) &#123;</span><br><span class="line">                objectLock.notify();</span><br><span class="line">                System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------通知&quot;</span>);</span><br><span class="line">            &#125;</span><br><span class="line">        &#125;, <span class="string">&quot;B&quot;</span>).start();</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br><span class="line"></span><br></pre></td></tr></table></figure>

<p>A线程暂停3秒钟，确保B线程先执行notify方法。B线程先notify（此时没有线程被暂停，没有唤醒任何线程），3秒钟过后，A线程继续执行，阻塞等待。一直没有线程将其唤醒。程序一直运行….</p>
<p>总结</p>
<ol>
<li>wait和notify方法必选要再同步代码快或者同步方法里面而且成对出现使用</li>
<li>遵循先wait后notify</li>
</ol>
<h3 id="Lock"><a href="#Lock" class="headerlink" title="Lock"></a>Lock</h3><p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225200739715.png" alt="image-20211225200739715"></p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">package</span> com.kylin;</span><br><span class="line"></span><br><span class="line"><span class="keyword">import</span> java.util.concurrent.TimeUnit;</span><br><span class="line"><span class="keyword">import</span> java.util.concurrent.locks.Condition;</span><br><span class="line"><span class="keyword">import</span> java.util.concurrent.locks.Lock;</span><br><span class="line"><span class="keyword">import</span> java.util.concurrent.locks.ReentrantLock;</span><br><span class="line"></span><br><span class="line"><span class="comment">/**</span></span><br><span class="line"><span class="comment"> * <span class="doctag">@author</span> kylin</span></span><br><span class="line"><span class="comment"> */</span></span><br><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">LockDemo</span> </span>&#123;</span><br><span class="line"></span><br><span class="line">    <span class="keyword">static</span> Lock lock = <span class="keyword">new</span> ReentrantLock();</span><br><span class="line">    <span class="keyword">static</span> Condition condition = lock.newCondition();</span><br><span class="line"></span><br><span class="line">    <span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">main</span><span class="params">(String[] args)</span> </span>&#123;</span><br><span class="line">        <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            lock.lock();</span><br><span class="line">            <span class="keyword">try</span> &#123;</span><br><span class="line">                System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------come in&quot;</span>);</span><br><span class="line">                condition.await();</span><br><span class="line">            &#125; <span class="keyword">catch</span> (InterruptedException e) &#123;</span><br><span class="line">                e.printStackTrace();</span><br><span class="line">            &#125; <span class="keyword">finally</span> &#123;</span><br><span class="line">                lock.unlock();</span><br><span class="line">            &#125;</span><br><span class="line">            System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------被唤醒&quot;</span>);</span><br><span class="line"></span><br><span class="line">        &#125;, <span class="string">&quot;A&quot;</span>).start();</span><br><span class="line"></span><br><span class="line">        <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            lock.lock();</span><br><span class="line">            <span class="keyword">try</span> &#123;</span><br><span class="line">                condition.signal();</span><br><span class="line">                System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------通知&quot;</span>);</span><br><span class="line">            &#125;<span class="keyword">finally</span> &#123;</span><br><span class="line">                lock.unlock();</span><br><span class="line">            &#125;</span><br><span class="line">        &#125;, <span class="string">&quot;B&quot;</span>).start();</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>将lock的<code>lock</code>和<code>unlock</code>操作注释。运行代码</p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225200915312.png" alt="image-20211225200915312"></p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225200952866.png" alt="image-20211225200952866"></p>
<p>同样运行抛出<code>java.lang.IllegalMonitorStateException</code>异常</p>
<p>接着我们同样是A线程先暂停3秒钟，确保B线程先运行，通知唤醒。</p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225201235308.png" alt="image-20211225201235308"></p>
<p>同样程序处于一直运行状态，A线程没有被唤醒。</p>
<p>这和使用<code>synchronized</code>是一样的问题，只不过对应Api有所区分。</p>
<p>传统的synchronized和Lock实现等待唤醒通知的约束</p>
<ul>
<li>线程先要获得并持有锁，必须在锁块（synchronized或lock）中</li>
<li>必须要先等待后唤醒，线程才能够被唤醒</li>
</ul>
<h3 id="LockSupport"><a href="#LockSupport" class="headerlink" title="LockSupport"></a>LockSupport</h3><p>通过<code>park()</code>和<code>unpark(thread)</code>方法来实现阻塞和唤醒线程的操作</p>
<p>LockSupport类使用一种名为<code>Permit</code>（许可）的概念来做到阻塞和唤醒线程的功能，每个线程都有一个许可(permit)，permit只有两个值1和0，默认是零。</p>
<p>可以把许可看成是一种(0,1)信号量（Semaphore）,但与Semaphore不同的是，许可的累加上限是1。</p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225204613398.png" alt="image-20211225204613398"></p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/**</span></span><br><span class="line"><span class="comment"> * <span class="doctag">@author</span> kylin</span></span><br><span class="line"><span class="comment"> */</span></span><br><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">LockSupportDemo</span> </span>&#123;</span><br><span class="line"></span><br><span class="line">    <span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">main</span><span class="params">(String[] args)</span> </span>&#123;</span><br><span class="line">        Thread a = <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------come in&quot;</span>);</span><br><span class="line">            <span class="comment">//被阻塞...等地啊通知等待放行，它要通过需要许可证</span></span><br><span class="line">            LockSupport.park();</span><br><span class="line">            System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------被唤醒&quot;</span>);</span><br><span class="line">        &#125;, <span class="string">&quot;A&quot;</span>);</span><br><span class="line">        a.start();</span><br><span class="line"></span><br><span class="line">        Thread b = <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            <span class="comment">//唤醒A线程</span></span><br><span class="line">            LockSupport.unpark(a);</span><br><span class="line">            System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------通知&quot;</span>);</span><br><span class="line">        &#125;, <span class="string">&quot;B&quot;</span>);</span><br><span class="line">        b.start();</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>接着同样是A线程暂停3秒钟，确保B线程先执行唤醒操作。</p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225204804986.png" alt="image-20211225204804986"></p>
<p>并没有出现抛出异常的情况，B线程运行3秒钟后，A线程正常运行，并被正常唤醒。</p>
<p>通过以上代码可以看出，LockSupport不需要同步代码块之类的前提，同时也支持先唤醒后等待这种操作。（先唤醒，后面的等待操作就没有用了，相当于抵消了）</p>
<h2 id="详解"><a href="#详解" class="headerlink" title="详解"></a>详解</h2><p>LockSupport是一个线程阻塞工具类，所有的方法都是静态方法，可以让线程在任意位置阻塞，阻塞之后也有对应的唤醒方法。总之，LockSupport调用的Unsafe中的native代码。</p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225205711360.png" alt="image-20211225205711360"></p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">park</span><span class="params">()</span> </span>&#123;</span><br><span class="line">    UNSAFE.park(<span class="keyword">false</span>, <span class="number">0L</span>);</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225205750274.png" alt="image-20211225205750274"></p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">unpark</span><span class="params">(Thread thread)</span> </span>&#123;</span><br><span class="line">    <span class="keyword">if</span> (thread != <span class="keyword">null</span>)</span><br><span class="line">        UNSAFE.unpark(thread);</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>LockSupport提供park()和unpark()方法来实现阻塞线程和解除线程阻塞的过程。</p>
<p>LockSupport和每个使用它的线程都有一个许可(permit)关联。permit相当于1，0的开关，默认是0。</p>
<p>调用一次unpark就加1，变成1。</p>
<p>调用一次park会消费permit，也就是将1变成0，同时park立即返回。</p>
<p>如再次调用park会变成阻塞（因为permit为零了会阻塞在这里，一直到permit变为1），这时调用unpark会把permit置为1。</p>
<p>每个线程都有一个相关的permit，permit最多只有一个，重复调用unpark也不会积累凭证。</p>
<p><img src= "https://gitee.com/kylincw/images/raw/master/loading.gif" data-lazy-src="https://qiniu.codekylin.cn/img/image-20211225210948916.png" alt="image-20211225210948916"></p>
<ol>
<li>A线程运行首先使用park()，将线程阻塞，permit为0。</li>
<li>B线程调用unpark(a)两次，permit由0+1=1变成了1，不能积累。</li>
<li>A线程不唤醒，再次调用park()，将线程阻塞，permit为0。没有唤醒操作，程序一直运行…</li>
</ol>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br></pre></td><td class="code"><pre><span class="line"></span><br><span class="line"><span class="comment">/**</span></span><br><span class="line"><span class="comment"> * <span class="doctag">@author</span> kylin</span></span><br><span class="line"><span class="comment"> */</span></span><br><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">LockSupportDemo</span> </span>&#123;</span><br><span class="line"></span><br><span class="line">    <span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">main</span><span class="params">(String[] args)</span> </span>&#123;</span><br><span class="line">        Thread a = <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            <span class="comment">//try &#123;</span></span><br><span class="line">            <span class="comment">//    TimeUnit.SECONDS.sleep(3);</span></span><br><span class="line">            <span class="comment">//&#125; catch (InterruptedException e) &#123;</span></span><br><span class="line">            <span class="comment">//    e.printStackTrace();</span></span><br><span class="line">            <span class="comment">//&#125;</span></span><br><span class="line">            System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------come in&quot;</span>);</span><br><span class="line">            <span class="comment">//被阻塞...等地啊通知等待放行，它要通过需要许可证</span></span><br><span class="line">            LockSupport.park();</span><br><span class="line">            LockSupport.park();</span><br><span class="line">            System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------被唤醒&quot;</span>);</span><br><span class="line">        &#125;, <span class="string">&quot;A&quot;</span>);</span><br><span class="line">        a.start();</span><br><span class="line"></span><br><span class="line">        Thread b = <span class="keyword">new</span> Thread(() -&gt; &#123;</span><br><span class="line">            <span class="comment">//唤醒A线程</span></span><br><span class="line">            LockSupport.unpark(a);</span><br><span class="line">            LockSupport.unpark(a);</span><br><span class="line">            System.out.println(Thread.currentThread().getName() + <span class="string">&quot;---------通知&quot;</span>);</span><br><span class="line">        &#125;, <span class="string">&quot;B&quot;</span>);</span><br><span class="line">        b.start();</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>线程阻塞需要消耗凭证（permit），这个凭证最多只有一个。</p>
<p>当调用park方法时</p>
<ul>
<li>如果有凭证，则会直接消耗掉这个凭证然后正常退出</li>
<li>如果无凭证，就必选阻塞等待凭证可用</li>
</ul>
<p>而unpark则相反，它会增加一个凭证，但凭证最多只能有1个，累加无效。</p>
<blockquote>
<p>为什么可以先唤醒线程后阻塞线程？</p>
</blockquote>
<p>因为unpark获得一个凭证，之后调用park方法，就可以名正言顺的凭证消费，故不会阻塞。</p>
<blockquote>
<p>为什么唤醒两次后阻塞两次，但最终结果还会阻塞线程？</p>
</blockquote>
<p>因为凭证的数量最多为1，连续调用两次unpark和调用一次unpark效果一样，只会增加一个凭证。而调用两次park却需要消耗两个凭证，证不够，不能放行。</p>
</article><div class="post-copyright"><div class="post-copyright__author"><span class="post-copyright-meta">文章作者: </span><span class="post-copyright-info"><a href="mailto:undefined">Kylin</a></span></div><div class="post-copyright__type"><span class="post-copyright-meta">文章链接: </span><span class="post-copyright-info"><a href="https://www.codekylin.cn/20208.html">https://www.codekylin.cn/20208.html</a></span></div><div class="post-copyright__notice"><span class="post-copyright-meta">版权声明: </span><span class="post-copyright-info">本博客所有文章除特别声明外，均采用 <a href="https://creativecommons.org/licenses/by-nc-sa/4.0/" target="_blank">CC BY-NC-SA 4.0</a> 许可协议。转载请注明来自 <a href="https://www.codekylin.cn" target="_blank">Kylin</a>！</span></div></div><div class="tag_share"><div class="post-meta__tag-list"><a class="post-meta__tags" href="/tags/JUC/">JUC</a><a class="post-meta__tags" href="/tags/LockSupport/">LockSupport</a></div><div class="post_share"><div class="social-share" data-image="https://qiniu.codekylin.cn/github/img/img/wallhaven-1j66e3.jpg" data-sites="facebook,twitter,wechat,weibo,qq"></div><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/social-share.js/dist/css/share.min.css" media="print" onload="this.media='all'"><script src="https://cdn.jsdelivr.net/npm/social-share.js/dist/js/social-share.min.js" defer></script></div></div><div class="post-reward"><div class="reward-button button--animated"><i class="fas fa-qrcode"></i> 打赏</div><div class="reward-main"><ul class="reward-all"><li class="reward-item"><a href="https://qiniu.codekylin.cn/img/20200807181442.jpg" target="_blank"><img class="post-qr-code-img" data-lazy-src="https://qiniu.codekylin.cn/img/20200807181442.jpg" alt="微信"/></a><div class="post-qr-code-desc">微信</div></li><li class="reward-item"><a href="https://qiniu.codekylin.cn/img/20200807181505.jpg" target="_blank"><img class="post-qr-code-img" data-lazy-src="https://qiniu.codekylin.cn/img/20200807181505.jpg" alt="支付寶"/></a><div class="post-qr-code-desc">支付寶</div></li></ul></div></div><nav class="pagination-post" id="pagination"><div class="prev-post pull-left"><a href="/59732.html"><img class="prev-cover" data-lazy-src="https://qiniu.codekylin.cn/github/img/img/博客封面14.png" onerror="onerror=null;src='/img/404.jpg'" alt="cover of previous post"><div class="pagination-info"><div class="label">上一篇</div><div class="prev_info">AQS抽象的队列同步器</div></div></a></div><div class="next-post pull-right"><a href="/25809.html"><img class="next-cover" data-lazy-src="https://qiniu.codekylin.cn/github/img/img/博客封面11.png" onerror="onerror=null;src='/img/404.jpg'" alt="cover of next post"><div class="pagination-info"><div class="label">下一篇</div><div class="next_info">SpringBoot整合shiro</div></div></a></div></nav><div class="relatedPosts"><div class="headline"><i class="fas fa-thumbs-up fa-fw"></i><span> 相关推荐</span></div><div class="relatedPosts-list"><div><a href="/60468.html" title="JUC之Callable接口"><img class="cover" data-lazy-src="https://qiniu.codekylin.cn/github/img/img/wallhaven-0pvrpm.jpg" alt="cover"><div class="content is-center"><div class="date"><i class="far fa-calendar-alt fa-fw"></i> 2020-09-27</div><div class="title">JUC之Callable接口</div></div></a></div><div><a href="/28239.html" title="JUC之synchronized和Lock"><img class="cover" data-lazy-src="https://qiniu.codekylin.cn/github/img/img/wallhaven-od5gj7.jpg" alt="cover"><div class="content is-center"><div class="date"><i class="far fa-calendar-alt fa-fw"></i> 2020-09-24</div><div class="title">JUC之synchronized和Lock</div></div></a></div><div><a href="/47426.html" title="JUC之公平锁和非公平锁"><img class="cover" data-lazy-src="https://qiniu.codekylin.cn/github/img/img/wallhaven-3kp6yv.jpg" alt="cover"><div class="content is-center"><div class="date"><i class="far fa-calendar-alt fa-fw"></i> 2020-09-26</div><div class="title">JUC之公平锁和非公平锁</div></div></a></div><div><a href="/23872.html" title="JUC之八锁问题"><img class="cover" data-lazy-src="https://qiniu.codekylin.cn/github/img/img/wallhaven-mdz9x9.jpg" alt="cover"><div class="content is-center"><div class="date"><i class="far fa-calendar-alt fa-fw"></i> 2020-09-24</div><div class="title">JUC之八锁问题</div></div></a></div><div><a href="/51393.html" title="JUC之可重入锁"><img class="cover" data-lazy-src="https://qiniu.codekylin.cn/github/images/20200601091329.jpg" alt="cover"><div class="content is-center"><div class="date"><i class="far fa-calendar-alt fa-fw"></i> 2020-09-26</div><div class="title">JUC之可重入锁</div></div></a></div><div><a href="/1215.html" title="JUC之强大的辅助类"><img class="cover" data-lazy-src="https://qiniu.codekylin.cn/github/img/img/wallhaven-nzj88g.jpg" alt="cover"><div class="content is-center"><div class="date"><i class="far fa-calendar-alt fa-fw"></i> 2020-09-26</div><div class="title">JUC之强大的辅助类</div></div></a></div></div></div><hr/><div id="post-comment"><div class="comment-head"><div class="comment-headline"><i class="fas fa-comments fa-fw"></i><span> 评论</span></div></div><div class="comment-wrap"><div><div class="vcomment" id="vcomment"></div></div></div></div></div><div class="aside-content" id="aside-content"><div class="card-widget card-info"><div class="card-info-avatar is-center"><img class="avatar-img" data-lazy-src="https://qiniu.codekylin.cn/img/20200807181526.jpg" onerror="this.onerror=null;this.src='https://qiniu.codekylin.cn/github/img/friend_404.gif'" alt="avatar"/><div class="author-info__name">Kylin</div><div class="author-info__description">学习不易，努力努力~</div></div><div class="card-info-data"><div class="card-info-data-item is-center"><a href="/archives/"><div class="headline">文章</div><div class="length-num">362</div></a></div><div class="card-info-data-item is-center"><a href="/tags/"><div class="headline">标签</div><div class="length-num">427</div></a></div><div class="card-info-data-item is-center"><a href="/categories/"><div class="headline">分类</div><div class="length-num">101</div></a></div></div><a class="button--animated" id="card-info-btn"><i class="fas fa-bookmark"></i><span>加入书签</span></a><div class="card-info-social-icons is-center"><a class="social-icon" href="https://github.com/kylincw" target="_blank" title="Github"><i class="iconfont icon-github"></i></a><a class="social-icon" href="tencent://message/?Menu=yes&amp;uin=171346168&amp;Service=300&amp;sigT=45a1e5847943b64c6ff3990f8a9e644d2b31356cb0b4ac6b24663a3c8dd0f8aa12a595b1714f9d45" target="_blank" title="qq"><i class="iconfont icon-qq"></i></a><a class="social-icon" href="https://space.bilibili.com/53836035" target="_blank" title="BiliBili"><i class="iconfont icon-bilibili-line"></i></a><a class="social-icon" href="mailto:zhang171346168@qq.com" target="_blank" title="Email"><i class="iconfont icon-email1"></i></a><a class="social-icon" href="/atom.xml" target="_blank" title="RSS"><i class="iconfont icon-rss"></i></a></div></div><div class="card-widget card-announcement"><div class="item-headline"><i class="fas fa-bullhorn card-announcement-animation"></i><span>公告</span></div><div class="announcement_content">学习不易，努力努力！</div></div><div class="sticky_layout"><div class="card-widget" id="card-toc"><div class="item-headline"><i class="fas fa-stream"></i><span>目录</span></div><div class="toc-content"><ol class="toc"><li class="toc-item toc-level-2"><a class="toc-link" href="#%E6%A6%82%E5%BF%B5"><span class="toc-number">1.</span> <span class="toc-text">概念</span></a></li><li class="toc-item toc-level-2"><a class="toc-link" href="#%E4%BD%BF%E7%94%A8"><span class="toc-number">2.</span> <span class="toc-text">使用</span></a><ol class="toc-child"><li class="toc-item toc-level-3"><a class="toc-link" href="#synchronized"><span class="toc-number">2.1.</span> <span class="toc-text">synchronized</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#Lock"><span class="toc-number">2.2.</span> <span class="toc-text">Lock</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#LockSupport"><span class="toc-number">2.3.</span> <span class="toc-text">LockSupport</span></a></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#%E8%AF%A6%E8%A7%A3"><span class="toc-number">3.</span> <span class="toc-text">详解</span></a></li></ol></div></div><div class="card-widget card-recent-post"><div class="item-headline"><i class="fas fa-history"></i><span>最新文章</span></div><div class="aside-list"><div class="aside-list-item"><a class="thumbnail" href="/56352.html" title="be动词"><img data-lazy-src="https://qiniu.codekylin.cn/github/img/img/博客封面10.png" onerror="this.onerror=null;this.src='/img/404.jpg'" alt="be动词"/></a><div class="content"><a class="title" href="/56352.html" title="be动词">be动词</a><time datetime="2022-07-12T11:47:29.800Z" title="更新于 2022-07-12 19:47:29">2022-07-12</time></div></div><div class="aside-list-item"><a class="thumbnail" href="/36436.html" title="JVM堆内存"><img data-lazy-src="https://qiniu.codekylin.cn/img/20200418115059.jpg" onerror="this.onerror=null;this.src='/img/404.jpg'" alt="JVM堆内存"/></a><div class="content"><a class="title" href="/36436.html" title="JVM堆内存">JVM堆内存</a><time datetime="2022-07-12T11:47:29.800Z" title="更新于 2022-07-12 19:47:29">2022-07-12</time></div></div><div class="aside-list-item"><a class="thumbnail" href="/44292.html" title="Java多线程详解"><img data-lazy-src="https://qiniu.codekylin.cn/github/img/img/wallhaven-eorjzk.png" onerror="this.onerror=null;this.src='/img/404.jpg'" alt="Java多线程详解"/></a><div class="content"><a class="title" href="/44292.html" title="Java多线程详解">Java多线程详解</a><time datetime="2022-07-12T11:47:29.800Z" title="更新于 2022-07-12 19:47:29">2022-07-12</time></div></div><div class="aside-list-item"><a class="thumbnail" href="/40200.html" title="谷粒商城记录"><img data-lazy-src="https://qiniu.codekylin.cn/github/img/img/wallhaven-6qvvrx.jpg" onerror="this.onerror=null;this.src='/img/404.jpg'" alt="谷粒商城记录"/></a><div class="content"><a class="title" href="/40200.html" title="谷粒商城记录">谷粒商城记录</a><time datetime="2022-07-12T11:47:29.800Z" title="更新于 2022-07-12 19:47:29">2022-07-12</time></div></div><div class="aside-list-item"><a class="thumbnail" href="/27082.html" title="Spring学习-3"><img data-lazy-src="https://qiniu.codekylin.cn/github/img/img/wallhaven-4x28xo.jpg" onerror="this.onerror=null;this.src='/img/404.jpg'" alt="Spring学习-3"/></a><div class="content"><a class="title" href="/27082.html" title="Spring学习-3">Spring学习-3</a><time datetime="2022-07-12T11:47:29.799Z" title="更新于 2022-07-12 19:47:29">2022-07-12</time></div></div></div></div></div></div></main><footer id="footer" style="background-image: url('https://qiniu.codekylin.cn/github/img/img/wallhaven-1j66e3.jpg')"><div id="footer-wrap"><div class="copyright">&copy;2019 - 2022 By Kylin</div><div class="framework-info"><span>框架 </span><a target="_blank" rel="noopener" href="https://hexo.io">Hexo</a><span class="footer-separator">|</span><span>主题 </span><a target="_blank" rel="noopener" href="https://github.com/jerryc127/hexo-theme-butterfly">Butterfly</a></div><div class="footer_custom_text"><a target="_blank" rel="noopener" href="https://beian.miit.gov.cn/"><img class="icp-icon" src="https://img.alicdn.com/tfs/TB1..50QpXXXXX7XpXXXXXXXXXX-40-40.png"><span>湘ICP备2022005420号-1</span></a></div></div></footer></div><div id="rightside"><div id="rightside-config-hide"><button id="readmode" type="button" title="阅读模式"><i class="fas fa-book-open"></i></button><button id="font-plus" type="button" title="放大字体"><i class="fas fa-plus"></i></button><button id="font-minus" type="button" title="缩小字体"><i class="fas fa-minus"></i></button><button id="translateLink" type="button" title="简繁转换">繁</button><button id="darkmode" type="button" title="浅色和深色模式转换"><i class="fas fa-adjust"></i></button><button id="hide-aside-btn" type="button" title="单栏和双栏切换"><i class="fas fa-arrows-alt-h"></i></button></div><div id="rightside-config-show"><button id="rightside_config" type="button" title="设置"><i class="fas fa-cog fa-spin"></i></button><button class="close" id="mobile-toc-button" type="button" title="目录"><i class="fas fa-list-ul"></i></button><a id="to_comment" href="#post-comment" title="直达评论"><i class="fas fa-comments"></i></a><button id="go-up" type="button" title="回到顶部"><i class="fas fa-arrow-up"></i></button></div></div><div id="local-search"><div class="search-dialog"><div class="search-dialog__title" id="local-search-title">本地搜索</div><div id="local-input-panel"><div id="local-search-input"><div class="local-search-box"><input class="local-search-box--input" placeholder="搜索文章" type="text"/></div></div></div><hr/><div id="local-search-results"></div><span class="search-close-button"><i class="fas fa-times"></i></span></div><div id="search-mask"></div></div><div><script src="/js/utils.js"></script><script src="/js/main.js"></script><script src="/js/tw_cn.js"></script><script src="https://cdn.jsdelivr.net/npm/instant.page/instantpage.min.js" type="module"></script><script src="https://cdn.jsdelivr.net/npm/vanilla-lazyload/dist/lazyload.iife.min.js"></script><script src="https://cdn.jsdelivr.net/npm/node-snackbar/dist/snackbar.min.js"></script><script src="/js/search/local-search.js"></script><div class="js-pjax"><script>function loadValine () {
  function initValine () {
    const valine = new Valine(Object.assign({
      el: '#vcomment',
      appId: 'ClIyIUhj1ue2rcRTsApYCR50-gzGzoHsz',
      appKey: 'ATug9IScYQBHILhKWEqBHYxM',
      placeholder: '昵称填入QQ号能获取到QQ头像哦~请输入正确的邮箱地址，你将会快速收到我的回复并且通过邮件通知你！~',
      avatar: 'robohash',
      meta: 'nick,mail,link'.split(','),
      pageSize: '10',
      lang: 'zh-cn',
      recordIP: false,
      serverURLs: 'https://cliyiuhj.lc-cn-n1-shared.com',
      emojiCDN: '',
      emojiMaps: "",
      enableQQ: true,
      path: window.location.pathname,
      requiredFields: ["nick,mail"],
      visitor: false
    }, null))
  }

  if (typeof Valine === 'function') initValine() 
  else getScript('https://cdn.jsdelivr.net/npm/valine/dist/Valine.min.js').then(initValine)
}

if ('Valine' === 'Valine' || !true) {
  if (true) btf.loadComment(document.getElementById('vcomment'),loadValine)
  else setTimeout(loadValine, 0)
} else {
  function loadOtherComment () {
    loadValine()
  }
}</script></div><script defer="defer" id="ribbon" src="https://cdn.jsdelivr.net/npm/butterfly-extsrc@1/dist/canvas-ribbon.min.js" size="150" alpha="0.6" zIndex="-1" mobile="false" data-click="true"></script><script defer="defer" id="fluttering_ribbon" mobile="false" src="https://cdn.jsdelivr.net/npm/butterfly-extsrc@1/dist/canvas-fluttering-ribbon.min.js"></script></div></body></html>